Camera with the function of changing the transmittance of liquid-crystal display device when abnormality is sensed

ABSTRACT

A camera has a liquid-crystal display device including a liquid crystal whose transmittance is variable. A sensing section senses an abnormality in the camera. A liquid-crystal control section, in a release signal wait mode, brings the liquid crystal of the liquid-crystal display device into a light-transmitting state and, when the sensing section has sensed an abnormality in the camera, changes the transmittance of the liquid crystal of the liquid-crystal display device.

BACKGROUND OF THE INVENTION

The present invention relates to a camera with a liquid-crystal displaydevice (hereinafter, referred to as an LCD).

Use of liquid crystal for a display in the finder of a camera has beenproposed. With such an LCD, the AF target mark, various modes, and theselection of field angle, such as panorama or normal, are represented onthe LCD screen. Positive LCDs, including guest-host LCDs and TN (twistednematic) LCDs, have been widely used.

Recently, the use of macromolecular dispersion liquid crystal for an LCDin the finder of a camera has been proposed, as disclosed Jpn. Pat.Appln. KOKAI Publication No. 5-165017. The macromolecular dispersionliquid crystal disclosed in the publication is a positive liquidcrystal, which prevents light from passing through when a voltage isapplied and allows light to pass through when no voltage is applied. Onthe other hand, negative liquid crystals have also been known. Theyallow light to pass through when a voltage is applied and prevent lightfrom passing through when no voltage is applied.

Since such a macromolecular dispersion liquid crystal display has a highdegree of scattering, use of such a display for the finder of a cameramakes the amount of light reaching the pupil very small. This enables afinder with a high contrast to be constructed, as compared with the TNLCD or guest-host LCD type. Conventional TN LCDs are available in thenegative and positive types. The types of liquid crystals usable for thefinder of a camera have been increasing in number these days.

With a conventional camera with the above-described liquid-crystaldisplay device, however, because the representation on theliquid-crystal display will not change even if an abnormality hasoccurred in the operation of the camera, the user cannot judge whetheran abnormality has occurred in the operation of the camera just bylooking at the liquid-crystal display device.

It is, accordingly, an object of the present invention to provide acamera which enables the user to judge properly whether an abnormalityhas occurred in the operation of the camera just by just looking at theliquid-crystal display device.

BRIEF SUMMARY OF THE INVENTION

The foregoing object is accomplished by providing a camera according toa first aspect of the present invention which has a liquid-crystaldisplay device including a liquid crystal whose transmittance isvariable, the camera comprising: a sensing section for sensing anabnormality in the camera; and a liquid-crystal control section which,in a release signal wait mode, brings the liquid crystal of theliquid-crystal display device into a light-transmitting state and, whenthe sensing section has sensed an abnormality in the camera, changes thetransmittance of the liquid crystal of the liquid-crystal displaydevice.

According to a second aspect of the present invention, there is provideda camera having a liquid-crystal display device in its finder, theliquid-crystal display device including a liquid crystal whosetransmittance is variable, the camera comprising: an actuating sectionfor actuating the camera; a sensing section for sensing an abnormalityin the operation of the camera caused by the actuating section; arelease signal output section; and a liquid-crystal control sectionwhich, in a release signal wait mode, brings the liquid crystal of theliquid-crystal display device into a light-transmitting state and, whenthe sensing section has sensed an abnormality in the camera, lowers thetransmittance of the liquid crystal of the liquid-crystal display deviceor changes the transmittance periodically.

Additional objects and advantages of the invention will be set forth inthe description which follows, and in part will be obvious from thedescription, or may be learned by practice of the invention. The objectsand advantages of the invention may be realized and obtained by means ofthe instrumentalities and combinations particularly pointed outhereinafter.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING

The accompanying drawings, which are incorporated in and constitute apart of the specification, illustrate presently preferred embodiments ofthe invention, and together with the general description given above andthe detailed description of the preferred embodiments given below, serveto explain the principles of the invention.

FIG. 1 is a conceptual diagram of a camera according to an embodiment ofthe present invention;

FIG. 2A is a front view of the camera 100 according to the embodimentand

FIG. 2B is a top view of the camera 100;

FIG. 3 shows a state where the user blocks the light from a self LED 52with a finger;

FIGS. 4A and 4B show a state where the light blocked by a finger issensed by a photometric sensor;

FIG. 5A is a circuit diagram of a blocking finger sensing section 9,

FIG. 5B shows a waveform of a signal for driving the self LED, and

FIG. 5C shows a waveform of the sensed signal;

FIG. 6 is a perspective view to help explain a modification of theblocking finger sensing;

FIG. 7 is a front view to help explain a method of sensing that the userhas pressed the pop-up section 56 during the flashing of the strobe;

FIGS. 8A, 8B, and 8C show the structure of a negative macromoleculardispersion LCD used in the embodiment;

FIG. 9A shows a segment pattern,

FIG. 9B a common pattern,

FIG. 9C a normal finder display,

FIG. 9D a panorama display, and

FIG. 9E a blackout display;

FIG. 10 is a flowchart to help explain part of the main flow of thecamera;

FIG. 11 is a flowchart to help explain another part of the main flow ofthe camera;

FIG. 12 is a flowchart to help explain another part of the main flow ofthe camera;

FIG. 13 is a flowchart to help explain still another part of the mainflow of the camera;

FIG. 14 is the first half of a flowchart to help explain the releaseprocess in detail;

FIG. 15 is the second half of the flowchart to help explain the releaseprocess in detail; and

FIG. 16 is a flowchart to help explain the abnormality handling processin detail.

DETAILED DESCRIPTION OF THE INVENTION

Hereinafter, referring to the accompanying drawings, an embodiment ofthe present invention will be explained in detail. FIG. 1 is aconceptual diagram of a camera according to an embodiment of the presentinvention. In FIG. 1, a CPU 1 is used to control various operations ofthe camera. It includes a timer 2. Connected to the CPU 1 are a powerswitch (barrier switch) 7 as a switch section, a release switch (releaseSW) 8 acting as a release signal output section, a blocking fingersensing section 9, an abnormal operation sensing section 10, a self-modeswitch (self-mode SW) 11, a battery check section 12, a rear coverswitch (rear cover SW) 13, a shutter section 6, a pop-up switch (pop-upSW) 81, an EEPROM 14, and a panorama switch (panorama SW) 59. A finder 3is also connected to the CPU 1 via an LCD driving section 5. An LCD(hereinafter, referred to as an in-F LCD) 4 is provided in the finder 3.

The embodiment is characterized in that the display is blacked out (orthe in-F LCD 4 is caused to prevent light from passing through) to givevarious representations or alarm messages by changing the transmittanceof the in-F LCD 4 under the control of the CPU 1 on the basis of variousinputs from the user and the result of sensing, such as a blockingfinger. For instance, they are as follows:

1) The in-F LCD 4 is changed from blackout to light-transmitting insynchronization with the turning on of the power switch 7. When thepower switch has turned on or a specific time has elapsed, the in-F LCD4 is returned to blackout display. This enables the user to judgewhether the camera is in the photograph enable mode or the photographdisable mode, just viewing the in-F LCD 4.

2) When exposure is made, the display of the in-F LCD 4 is blacked out.This enables the user to know that exposure has been made, just viewingthe in-F LCD 4.

3) When the blocking finger sensing section 9 has sensed that a fingeras an obstruction covering the distance-measuring section, photometricsection, or strobe section prevents the proper distance measurement,photometry, or strobe operation, the display of the in-F LCD 4 isblacked out. In addition, when the popup switch 81 has sensed that theuser has pressed the strobe section, the in-F LCD 4 is also blacked out.Alternatively, the transmittance of the liquid-crystal display device ischanged periodically. On the basis of the blackouts, the user can knownot only that a finger has covered the camera but also that the strobesection has been pressed, just viewing the in-F LCD 4.

4) When the user operates the self-mode switch 11 and brings the camerainto the self mode, the display of the in-F LCD 4 is blacked out. Thisenables the user to know that the camera is not in the normal exposurestate, just seeing the in-F LCD 4.

5) The battery check section 12 senses the battery voltage. If thebattery voltage is lower than a specific voltage, the display of thein-F LCD 4 will be blacked out. This enables the user to know that thepower supply is running out, just viewing the in-F LCD 4.

6) The liquid-crystal display is blacked out by lowering thetransmittance of the in-F LCD 4 temporarily in synchronization with therelease switch 8. In this case, the time during which the transmittanceis lowered temporarily is measured by the timer 2 and so controlled thatit is longer than the shutter open time in exposure. This enables theuser to judge whether a picture has been taken.

7) When the abnormal operation sensing section 10 has sensed an abnormaloperation of the camera and the proper operation of the camera cannot beguaranteed, not only is the release switch 8 prevented from beingpressed but also the in-F LCD 4 is blacked out. This enables the user toknow that the camera is abnormal, just viewing the in-F LCD 4.

8) When various operations of the camera are being carried out, forinstance, when the autoload operation is being carried out with the rearcover switch 13 being closed, not only is the release switch preventedfrom being pressed but also the in-F LCD 4 is blacked out. This enablesthe user to know that exposure cannot be made, just seeing the in-F LCD4. When the user operates a panorama switch 59, explained later, thescreen size is changed. Then, the changed screen is caused to allowlight to pass through and the remaining portion is forced to preventlight from passing through. This enables the user to know that thepanorama display is in operation, just viewing the in-F LCD 4.

FIG. 2A is a front view of the camera 100 and FIG. 2B is a top view ofthe camera 100. An AF window 53, a finder 54, a photometric window 55,and a self LED 52 are provided at the top middle of the front of thecamera. Below them, there is provided a lens tube 51. The lens tube 51houses a camera optical system and is capable of moving in and out. Onthe right side of the front, a barrier 50 is provided. An externalliquid-crystal display section 70 is provided in the middle of the topface of the camera and can display the date, various camera modes, andframe number. When the camera is viewed from the front, a release SW 58and a zoom SW 57 are provided on the left side of the top face and apop-up section 56 incorporating a strobe flashing section is provided onthe right side of the top face. In addition, at the back of the camera,there is provided a slidable panorama SW 59.

Hereinafter, the operation of sensing a finger blocking the light at theblocking finger sensing section 9 will be explained in detail. FIG. 3 isa perspective view of the camera illustrating a state where the user hasblocked the light from the self LED 52 with a finger. The light blockedby a finger enters at the photometric window 55. The light passingthrough the photometric window 55 is gathered by a condenser lens 61 andsensed by a photometric sensor 62 as shown in FIG. 4A. The photometricsensor 62 is composed of a photometric section 62-1 and a blockingfinger sensing light-receiving section 62-2. The photometric section62-1 performs normal photometry. An infrared LED may be used in place ofthe self LED 52.

FIG. 5A shows a circuit configuration of the blocking finger sensingsection 9. A signal S_(LED) from the CPU 1 causes the self LED 52 toemit light. FIG. 5B shows a waveform of the signal S_(LED). When thelight has not been blocked by a finger, no light enters the blockingfinger sensing light-receiving section 62-2. As a result, the waveformof the signal AD0 inputted from the light-receiving section 62-2 to anA/D converter 63 of the CPU 1 is as shown in FIG. 5B. In contrast, whenthe light has been blocked by a finger, the light from the self LED 52blocked by a finger 60 enters the blocking finger sensinglight-receiving section 62-2. As a result, the waveform of the signalAD0 inputted to the A/D converter 63 of the CPU 1 is as shown in FIG.5C. In this way, the state where a finger has blocked the light issensed.

FIG. 6 is a perspective view of the camera to help explain amodification of the process of sensing that a finger has blocked thelight. To sense a finger blocking the light, an infrared LED 70 and alight-receiving section 71 are provided in the pop-up section 56. When afinger 60' of the user has blocked the light from the infrared LED 70,the light strikes the light-receiving section 71, which then senses it.The detail of sensing is the same as when the light from the self LED 52has been blocked in the embodiment. Thus, explanation of it will not begiven here.

FIG. 7 is a front view of the camera to help explain a method of sensinga state where the user has pressed the pop-up section 56 during theflashing of the strobe. As shown in FIG. 7, the pop-up SW 81 and a metalstrip 80 are provided at the front of the camera 100. When the userpresses the pop-up section 56, the pop-up SW 81 turns off. When thepop-up section 56 is in the up position, the pop-up SW 81 is on.Therefore, sensing the state of the pop-up SW 81 makes it possible tosense a state where the pop-up section has been pressed.

FIGS. 8A, 8B, and 8C show a configuration of a negative macromoleculardispersion LCD used in the embodiment. As shown in FIGS. 8A, 8B, and 8C,a pair of alignment films 112-1, 112-2, a pair of electrodes 111-1,111-2, and a pair of glass substrates 110-1, 110-2 are provided in thatorder, with macromolecular particles 113 between them. FIG. 8A shows theno-light-transmitting state where no pulse voltage is applied. In thisstate, the incident light 107 is outputted in the form of scatteredlight 108. FIG. 8B shows the light-transmitting state where a pulsevoltage is applied. In the state, the incident light 107 is outputted inthe form of emitted light 120.

FIG. 8C shows the relationship between the driving pulse voltage of theLCD and the transmittance. As shown in FIG. 8C, as the applied voltageincreases, the transmittance increases. In the embodiment, theno-light-transmitting state with a first transmittance, thelight-transmitting state with a third transmittance, and a secondtransmittance between the first and third transmittances are used.

While in the embodiment, the negative LCD has been used, a positivemacromolecular dispersion LCD may be used, as disclosed in, for example,Jpn. Pat. Appln. KOKAI Publication No. 5-165017.

FIG. 9A shows a segment pattern on the lower glass substrate 110-2. Thesegment pattern is made up of a pattern 121 related to a SEG 1electrode, a pattern 120 related to a SEG 2 electrode, and a pattern 122related to a COM electrode. Three openings 120A, 120B, and 120C are madein the pattern 121. Numeral 123 indicates a connecting section. FIG. 9Bshows a common pattern on the upper glass substrate 110-1. The commonpattern has a connecting section 123' connected to the connectingsection 123.

FIG. 9C illustrates a normal finder display, in which the three segmentpatterns and openings in FIG. 9A are shown. FIG. 9D illustrates apanorama display, which shows the state where the patterns 120 and 122are caused to prevent light from passing through (or to block light) andthe pattern 121 is forced to allow light to pass through. FIG. 9Eillustrate a blackout display, in which all the patterns are caused toprevent light from passing through and go black.

Hereinafter, the main flow of the camera will be described in detail byreference to FIG. 10. The change of the barrier or rear cover gives riseto an interrupt, which starts a process at step S0 (PWRST). The stackpointer is cleared (step S1) and then the in-F LCD 4 is turned on tochange from the no-light-transmitting state to the light-transmittingstate (step S2). Next, a rear cover state flag F₋₋ BKCLOS, camera statedata CNDT, and a damage flag are read from the EEPROM 14 (step S3). Whenthe rear cover state flag F₋₋ BKCLOS has a value of 0, this means thatthe rear cover is closed, whereas when it has a value of 1, this meansthat the rear cover is open. For the camera state data CNDT, 0 means thenormal state (or release enable), 1 means one-frame winding, 2 meansautoloading, and 3 means rewinding. The damage flag includes three typesof flag: F₋₋ WNDDMG meaning a failure in one-frame winding, F₋₋ ALDDMGmeaning a failure in autoloading, and F₋₋ RWDDMG meaning a failure inrewinding.

Next, from the state of the rear cover state flag F₋₋ BKCLOS, it isjudged whether the rear cover has been changed (step S4). If it has(YES), it will be judged whether the rear cover has been closed (stepS5). If it has (YES), "0" will be substituted into the rear cover stateflag F₋₋ BKCLOS (step S6) and "2" be substituted into the camera statedata CNDT (step S7) and control will proceed to step S8.

If the rear cover has not been closed (NO) at step S5, "1" will besubstituted into the rear cover state flag F₋₋ BKCLOS (step S12) and "0"be substituted into the camera state data CNDT (step S13). Then, controlwill proceed to step S8.

At step S8, the damage flag F₋₋ WNDDMG is cleared. At step S9, thedamage flag F₋₋ ALDDMG is cleared. At step S10, the damage flag F₋₋RWDDMG is cleared. Next, control goes to step S11, where the rear coverstate flag F₋₋ BKCLOS, camera state data CNDT, and damage flag arewritten into the EEPROM 14.

After step 11 has been executed or when the result at step S4 is NO,control proceeds to step S14. At step S14, a check is made to see if thecamera state data CNDT has a value of 2 (in the course of autoloading).If it has (YES), control will proceed to step S16, where autoloadingwill be effected. Depending on whether the autoloading has been donesuccessfully, the damage flag F₋₋ RWDDMG is set at step S16. Next, acheck is made to see if the damage flag F₋₋ ALDDMG has a value of 0(step S17). If it has not (NO), control will go to step S110, where anabnormality handling process (DAMAG) will be executed, which willexplained later. If it has (YES) at step S17, "0" will be substitutedinto the camera state data CNDT (step S18) to enable a release action.Thereafter, the damage flag F₋₋ WNDDMG will be cleared (step S19) andthen the damage flag F₋₋ RWDDMG be cleared (step S20). Next, controlwill proceed to step S21, where the rear cover state flag F₋₋ BKCLOS,camera state data CNDT, and damage flag will be written into the EEPROM14.

If the camera state data CND has not a value of 2 (NO) at step S14,control will go to step S15, where it is judged whether the damage flagF₋₋ ALDDMG has a value of 1. If it has (YES), this means a failure inthe autoloading and therefore control will go to step S16 to execute theabove-described steps to effect autoloading again.

After step S21 has been executed or when the damage flag F₋₋ ALDDMG hasnot a value of 1 (NO) at step S15, control goes to step S23 in FIG. 11.At step S23, it is judged whether the camera state data CNDT has a valueof 1. If it has (YES), control will proceed to step S25. If it has not(NO) at step S23, control will proceed to S24, where a check will bemade to see if the damage flag F₋₋ WNDDMG has a value of 1. If it hasnot (NO), control will proceed to step S25.

At step S25, one-frame winding is done. Depending on whether one-framewinding has been done successfully, the damage flag F₋₋ WNDDMG is set atstep S25. Next, it is judged whether damage flag F₋₋ WNDDMG has a valueof 0 (step S26). If it has not (NO), control will proceed to step S111,where an abnormality handling process (DAMAG) will be executed, whichwill be explained later. If it has (YES), the damage flag F₋₋ RWDDMGwill be cleared (step S28).

Next, control goes to step S29, where the rear cover state flag F₋₋BKCLOS, camera state data CNDT, and damage flag are written into theEEPROM 14.

After step S29 has been executed or when the damage flag F₋₋ WNDDMG hasnot a value of 1 (NO) at step S24, control goes to step S30, where acheck is made to see if the camera state data CNDT has a value of 3. Ifit has (YES), control will proceed to step S32. If it has not (NO), itwill be judged at step S31 whether the damage flag F₋₋ RWDDMG has avalue of 1. If it has (YES), control will go to step S32. At step S32,rewinding is done and a check is made to see if the damage flag F₋₋RWDDMG has a value of 0. If it has not (NO), this means a failure inrewinding and therefore control will proceed to step S112 to effectrewinding again, where an abnormality handling process (DAMAG) will beexecuted, which will be explained later.

When NO at step S31 or when YES at step S33, control goes to step S34 inFIG. 12, where the stack pointer is cleared. Then, at step S35, a checkis made to see if the barrier is open. If it is not (NO), control willjump to step S54. If it is (YES), the zoom will be set to the wideposition (step S36). Next, it is judged whether the zoom operation atstep S36 has been proper (step S37). If it has not (NO), control willproceed to step S113, where an abnormality handling process (DAMAG) willbe executed. If it is (YES), control will go to step S38, where afour-minute timer will be started.

Next, control goes to step S39, where a check is made to see if thebarrier has changed. If it has (YES), control will proceed to step S114(PWRST). If it has not (NO), control will go to step S40, where a checkwill be made to see if the rear cover has changed. If it has (YES),control will proceed to step S115 (PWRST). If it has not (NO), controlwill go to step S41, where it will be judged whether the zoom SW hasbeen operated. If it has (YES), zooming control will be executed (stepS42). Next, it is judged whether the zoom operation at step S42 has beenproper (step S43). If it has not (NO), control will proceed to stepS116, where an abnormality handling process (DMAG) will be executed.

When the rear cover has not been changed (NO) at step S41, or when thezoom operation has been proper (YES) at step 43, control goes to stepS44, where a check is made to see if the release SW has been operated.If it has (YES), the release process (R1) will be carried out (step S45)and then control will jump to step S23 (FIG. 11). If the zoom operationhas not been proper (NO) at step S44, control will go to step S46, wherean external LCD display will be made according to the mode. Next, acheck is made to see if the strobe has been covered with a finger (stepS47). If it has (YES), the in-F LCD will be blacked out (step S48). Thedriving pulse voltage of the LCD may be lowered to provide atransmittance between transmission and non-transmission. Alternatively,transmission may alternate with non-transmission. To do this, a circuitfor alternating between transmission and non-transmission is providedand turned on and off by software.

After step S48 has been executed or when the strobe has not been coveredwith a finger (NO) at step S47, control goes to step S49, where it isjudged whether the pop-up section 56 has been pressed to turn off thepop-up SW. If it has (YES), the in-F LCD will be blacked out (step S50).

After step S50 has been executed or when the pop-up section 56 has notbeen pressed (NO) at step S49, control goes to step S51, where thedistance-measuring section or the photometric section has been coveredwith a finger (step S51). If it has (YES), the in-F LCD will be blackedout (step S52).

After step S52 has been executed or when neither the distance-measuringsection nor the photometric section has been covered with a finger (NO)at step S51, control proceeds to step S53, where a check is made to seeif four minutes have elapsed. If they have not (NO), control will returnto step S39. If they have (YES), the in-F LCD will be turned off tochange from the light-transmitting state to the no-light-transmittingstate (step S54). Next, control proceeds to step S55, where the externalLCD is turned off and the zoom is retracted fully (step S56). Next,control goes to step S57, where it is judged whether the zoom operationis proper. If it is not (NO), control will proceed to step S117, wherean abnormality process (DAMAG), explained layer, will be carried out. Ifit is (YES), control will proceed to step S58, where the cameraoperation will be stopped.

Next, the release process (R1) will be described in detail by referenceto the flowchart of FIG. 14. First, distance measuring and photometryare carried out (step S60). Then, it is judged whether the self mode ison (step S61). If it is (YES), the in-F LCD will be turned off to changefrom the light-transmitting state to the no-light-transmitting state(step S62). Next, the LCD is caused to blink to provide a self-display(step S63). Then, the in-F LCD is turned on to change from theno-light-transmitting state to the light-transmitting state (step S64).

After step S64 has been executed or when the self mode is not on (NO) atstep S61, control goes to step S65, where the lens is brought into focusaccording to the result of distance measuring. Then, control goes tostep S66, where it is judged whether the lens operation at step S65 hasbeen proper. If it has not (NO), control will proceed to step S118,where an abnormality handling process (DAMAG) will be carried out. If ithas (YES), control will proceed to step S67, where a check will be madeto see if the red eye reduction mode is on. If it is (YES), pre-lightemission will be carried out to reduce red eye (step S68).

After step S68 has been executed or when the red eye reduction mode isnot on (NO) at step S67, control goes to step S69, where the in-F LCD isbrought into the no-light-transmitting state. The transmittance of thein-F LCD may be lowered. After a 50-ms timer has been started at stepS70, shutter control is carried out at step S71. Next, it is judgedwhether the shutter operation is proper (step S72). If it is not (NO),control will go to step S119, where an abnormality process (DAMAG) willbe performed. If it is (YES), control will proceed to step S73, where acheck will be made to see if the 50-ms timer has expired. If it has not(NO), control will wait for the timer to expire. Once the timer hasexpired, control will go to step S74, where the in-F LCD will be causedto allow light to pass through. Waiting for 50 ms at step S73 causes thedisplay to be blacked out for at least 50 ms even when the shutteroperates at high speed, which enables the user to know reliably thatexposure has been made. Next, the lens is driven for resetting (stepS75). Then, it is judged whether the lens operation at step S75 has beenproper (step S76). If it has not (NO), control will proceed to stepS120, where an abnormality handling process (DAMAG) will be carried out,which will be explained later. If it has (YES), it will be judgedwhether the rear cover is closed (step S77). If it is (YES), it will bejudged whether film has been loaded (step S78). If it has (YES), "1"will be substituted into the camera state data CNDT (step S79) to setone-frame winding. Thereafter, the rear cover state flag, camera statedata, and damage flag will be written into the EEPROM 14 (step S80).Then, control will return. In addition, if the result is NO at step S77and step S78, control will return.

Using the flowchart of FIG. 16, the abnormality handling process will bedescribed in detail. First, the stack pointer is cleared (step S100) andthe in-F LCD starts to blink at 1 Hz (in this case, the in-F LCDalternates between transmission and non-transmission) (step S101). Next,after the four-minute timer has been started (step S102), it is judgedwhether the barrier has changed (step S103). If it has not (NO), it isjudged whether the rear cover has changed (step S104). If it has not(NO), it is judged whether four minutes have elapsed (step S105). Ifthey have (YES), the in-F LCD will be turned off to present theno-light-transmitting state (step S106). If they have not (NO), controlwill return to step S103. Then, control will go to step S107, where theexternal LCD display will be turned off and the camera operation bestopped (step S108). If YES at step S103 or S104, control will return to"PWRST" at steps S121 and S122.

In the above embodiment, the in-F LCD 4 is blinked when an abnormalityin the function of the camera has occurred. Alternatively, thetransmittance of the liquid-crystal display can be lowered constantlywhen the abnormality has occurred. The blinking operation or thelowering operation in the transmittance can also be used when the objectis too near to take a picture or when the AF operation cannot berealized because of the low contrast of the object in the passive-typeAF. In addition, The blinking operation or the lowering operation in thetransmittance can also be used when one cannot take a picture properlyalthough it is not a malfunction, which includes those when a filmcannot be fed properly or a strobe is not charged or the extent in whichan AF operation is possible is exceeded.

The present invention enables the user to judge properly whether anabnormality has occurred in the operation of the camera, just looking atthe liquid-crystal display device.

Additional advantages and modifications will readily occur to thoseskilled in the art. Therefore, the invention in its broader aspects isnot limited to the specific details and representative embodiments shownand described herein. Accordingly, various modifications may be madewithout departing from the spirit or scope of the general inventiveconcept as defined by the appended claims and their equivalents.

What is claimed is:
 1. A camera with a liquid-crystal display deviceincluding a liquid crystal whose transmittance is variable, the cameracomprising:a sensing section for sensing an abnormality in the camera;and a liquid-crystal control section which, in a release signal waitmode, brings the liquid crystal of the liquid-crystal display deviceinto a light-transmitting state and, when the sensing section has sensedan abnormality in the camera, changes the transmittance of the liquidcrystal of the liquid-crystal display device; wherein, even while thetransmittance of the liquid crystal is being changed, when anopening/closing state of a lens barrier or rear cover of the camera ischanged the liquid-crystal control section restores the liquid crystalto the light-transmitting state and an initial operation of the camerais re-performed.
 2. A camera according to claim 1, wherein theliquid-crystal control section changes the transmittance of the liquidcrystal periodically on the basis of an abnormality sense output fromthe sensing section.
 3. A camera according to claim 1, wherein thesensing section senses whether an obstruction is present in front of thecamera.
 4. A camera according to claim 1, wherein the sensing sectionsenses whether an obstruction is present in front of the camera and theliquid-crystal control section lowers the transmittance of the liquidcrystal or changes the transmittance periodically when the sensingsection has sensed that an obstruction is present.
 5. A camera accordingto claim 1, further comprising a photometric section, wherein thesensing section senses whether an obstruction is present in front of thephotometric section.
 6. A camera according to claim 1, furthercomprising a photometric section, wherein the sensing section senseswhether an obstruction is present in front of the photometric sectionand the liquid-crystal control section lowers the transmittance of theliquid crystal or changes the transmittance periodically when thesensing section has sensed that an obstruction is present in front ofthe photometric section.
 7. A camera according to claim 1, furthercomprising a distance-measuring section, wherein the sensing sectionsenses whether an obstruction is present in front of thedistance-measuring section.
 8. A camera according to claim 1, furthercomprising a distance-measuring section, wherein the sensing sectionsenses whether an obstruction is present in front of thedistance-measuring section and the liquid-crystal control section lowersthe transmittance of the liquid crystal or changes the transmittanceperiodically when the sensing section has sensed that an obstruction ispresent in front of the distance-measuring section.
 9. A cameraaccording to claim 1, further comprising a strobe, wherein the sensingsection senses whether an obstruction is present in front of the strobe.10. A camera according to claim 1, further comprising a strobe, whereinthe sensing section senses whether an obstruction is present in front ofthe strobe and the liquid-crystal control section lowers thetransmittance of the liquid crystal or changes the transmittanceperiodically when the sensing section has sensed that an obstruction ispresent in front of the strobe.
 11. A camera according to claim 1,further comprising a pop-up strobe, wherein the sensing section senseswhether the popped-up strobe has been pressed down.
 12. A cameraaccording to claim 1, further comprising a pop-up strobe, wherein thesensing section senses whether the popped-up strobe has been presseddown and the liquid-crystal control section lowers the transmittance ofthe liquid crystal or changes the transmittance periodically when thesensing section has sensed that the popped-up strobe has been presseddown.
 13. A camera according to claim 1, wherein the sensing section isa battery check section for sensing whether the power supply voltage ofthe camera is lower than a specific voltage.
 14. A camera according toclaim 1, wherein the sensing section is a battery check section forsensing whether the power supply voltage of the camera is lower than aspecific voltage and the liquid-crystal control section lowers thetransmittance of the liquid crystal or changes the transmittanceperiodically when the battery check section has sensed that the powersupply voltage is lower than the specific voltage.
 15. A cameraaccording to claim 4, wherein, when the sensing section has sensed anabnormality in the camera, the liquid-crystal control section lowers thetransmittance of the liquid crystal to a blackout state where thetransmittance of the liquid crystal is almost zero.
 16. A cameraaccording to claim 1, wherein the liquid-crystal control section isprovided in a finder in the camera.
 17. A camera according to claim 1,wherein the camera is a zooming camera, the sensing section senseswhether an abnormality has occurred in the zooming operation, and theliquid-crystal control section lowers the transmittance of the liquidcrystal or changes the transmittance periodically when the sensingsection has sensed that an abnormality has occurred in the zoomingoperation.
 18. A camera according to claim 1, wherein the sensingsection senses whether an abnormality has occurred in a film feedoperation and the liquid-crystal control section lowers thetransmittance of the liquid crystal or changes the transmittanceperiodically when the sensing section has sensed that an abnormality hasoccurred in the film feed operation.
 19. A camera having aliquid-crystal display device in its finder, the liquid-crystal displaydevice including a liquid crystal whose transmittance is variable, thecamera comprising:an actuating section for actuating the camera; asensing section for sensing an abnormality in the operation of thecamera caused by the actuating section; a release signal output section;and a liquid-crystal control section which, in a release signal waitmode, brings the liquid crystal of the liquid-crystal display deviceinto a light-transmitting state and, when the sensing section has sensedan abnormality in the camera, lowers the transmittance of the liquidcrystal of the liquid-crystal display device or changes thetransmittance periodically; wherein, even while the transmittance of theliquid crystal is being changed, when an opening/closing state of a lensbarrier or rear cover of the camera is changed the liquid-crystalcontrol section restores the liquid crystal to the light-transmittingstate and an initial operation of the camera is re-performed.
 20. Acamera according to claim 19, wherein, when the sensing section hassensed an abnormality in the camera, the liquid-crystal control sectionlowers the transmittance of the liquid crystal to a blackout state wherethe transmittance of the liquid crystal is almost zero.
 21. A cameraaccording to claim 19, wherein the liquid-crystal display device is anegative macromolecular dispersion liquid crystal.